Agitator for mash tanks



Jan. 25, 1938. v A. R. KELLVER 2,106,529

AGITATOR FOR MASH TA NKS Filed July 23, 1937 Patented Jan. 25, 1938 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to agitating apparatus, and more particularly to such apparatus especially designed to agitate a machine of the type used for brewing beer or similar beverages.

One feature of this invention is that it provides improved agitation, resulting in a better extraction of the desired ingredients from the solids used in such brewing; another feature of this invention is that it is adapted to achieve such improved agitation with less power than now used on such agitators; yet another feature of this invention is that the agitating apparatus is so designed that clogging is prevented; other features and advantages of this invention will be apparent from the following specification and the drawing, in which:

Fig. l is a partial top plan view of a tank having therein agitating apparatus embodying this invention; Fig. 2 is a vertical sectional view of the same tank; Fig. 3 is an end elevation of the blades and scoops mounted thereon; and Fig. 4 is a vector diagram of certain of the forces developed.

In the process of brewing beer and similar beverages various solids, such as malt, hops, barley and the like are mixed with water to achieve the desired extraction, and thus certain tanks in the process, such as rice tanks, mash tuns, and brew kettles, have therein amixture comprising both liquid and solids. In order to extract as much as possible of the desired elements from the solids it is necessary that these mixtures be agitated, and such tanks are generally provided with agitating apparatus of various kinds, driven by a prime mover of some type external of the tanks.

The present invention provides improved agitating means, which not only so distributes the solids through the liquid as to secure better extraction, but may be operated with less power than conventional types of agitators. The agitator comprises in general a propeller consisting of two inclined blades, each blade having mounted thereon substantially tubular inclined scoops.

In the particular embodiment of the invention illustrated herewith a tank H), which may be of i any desired shape, is here shown as having substantially cylindrical side walls H and a straight bottom l2, the bottom being provided with an outlet l3 which may be closed by valve means, not here shown, since it forms no part of the present invention. The tank has angularly disposed therein near the periphery thereof a heating tube or coil l4, adapted to have steam or any other hot fluid passed therethrough in heat transfer relation to the mixture in the tank. The tank, tube, and other metal parts within the tank are preferably of copper, although they may be of any metal adapted to withstand exposure to the mixtures in the tank.

The tank is here shown as having extending therein through the bottom thereof a rotatable shaft [5, which shaft is journaled in a suitable bearing l6 and connected to some prime mover, not here shown, in order that rotation thereof may be effected. Within the tank the shaft l5 carries a propeller ll, here shown as comprising a hub 18 and blades l9 and 20. These blades are similar, each being mounted on the opposite side of the shaft from the other and beingperpendicular thereto so that they lie in a substantially horizontal plane. The blades are relatively thin throughout the major part of their width, andare laterally inclined, as may be particularly seen from Fig. 3. This inclination is about 30, and the lower end is on the forward part of the blade and lies closely adjacent the bottom of the tank. When the forward part is spoken of, it is meant that part which is the leading edge during rotation of the propeller, and first contacts the mixture in the tank. In the particular embodiment of the device illustrated herewith the agitator is adapted to rotate in a clockwise direction, viewed from above, as may be seen from a consideration of Fig. 1.

Each of the blades has mounted thereon and carried closely thereabove a plurality of tubular scoops. Since the arrangement of these scoops on each blade is identical only those on the blade 20 will be described. Each scoop is of closed tubular form, of any cross-sectional shape, being here shown as of substantially cylindrical form, without any slots or openings therethrough or any projections which might cause solids to pack thereagainst. The scoops preferably decrease in size toward the end of the blade, are set at an angle of with the horizontal, and are i of sufiicient length that their upper or rear ends extend slightly above the normal upper level of the solids 2i in the tank. Reference to Fig. 2 will show that the tank has therein a liquid 22 as well as the solids, but that the solids normally tend to settle to the bottom as illustrated.

In an 13-foot tank, for example, the scoop 23 would have its center about seventeen inches from the center of the shaft l5, and would have a diameter of about nine inches, and a length along a horizontal projection of about eighteen inches. That is, although the walls of the scoop are inclined at an angle of 30 to the horizontal the two ends are preferably vertical. Succeeding scoops might well be. placed about twelve inches apart, with respect to their centers, and would progressively decrease in. size. That is, scoop 24 should be about eight inches, scoop 25, seven inches, scoop 26, six inches, and scoop 21, five inches in diameter. It will be noted that the bottom lines of the scoops are all on the same horizontal level, rather than the center.

Rotation of the propeller and scoop causes the solids 2! to be thrown upwardly as a result of contact with the forwardly moving inclined surfaces of the propeller blades and scoops. Material which enters the scoops is thrown up into the liquid 22, having an upward component of force as it leaves the back end of the scoops. This will be readily understood from consideration of the vector diagram in Fig. 4. Assuming the agitator is being rotated such that solids enter any particular scoop with a 90-pound force, the force along the direction which the material travels through and leaves the scoops is about 80 pounds, as illustrated. Thus, as the material leaves the scoop it would have an 80-pound force in the direction 30 upwardly from the horizontal, which might again be resolved into a 40-pound upward vertical component and about a 70-pound horizontal component. The upward force developed would cause the solids to rise considerably in the liquid in the tank, so that the desired extraction might be achieved as they settle back. The upper surfaces of the blades, of course, also throw the solids upwardly with a similar action and a similar diagram of forces, although to a lesser extent.

The particular agitating apparatus illustrated herewith achieves a very thorough mixing of the solids with the liquid, and the: desired extraction. with a minimum expenditure of power. All parts contacting the solids in the mixture are so shaped and arranged as to have little dead loss, as much power as possible being converted into an upward or vertical component of motion. The decreasing size of the scoops enables the blades to be rotated at reasonable speed without undue resistance.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims, in which it is my intention to claim all novelty inherent in my invention as broadly as permissible, in view of the prior art.

I claim:

1. Agitating apparatus of the character described for a tank adapted to hold a mixture comprising fluid and solids, including: a vertical rotatable shaft; mounted on said shaft and extending in opposite directions therefrom, said blades being laterally inclined and having their lower edges on the forward side and closely adjacent the bottom of said tank; and a plurality of inclined tubular scoops mounted on said blades, said scoops all having their lower ends forward and progressively decreasing in diameter toward the ends of said blades.

2. Agitating apparatus of the character described for a tank adapted to hold a mixture comprising a fluid and solids, including: a vertical rotatable shaft; a pair of horizontal blades mounted on said shaft and extending in opposite directions therefrom, said blades being laterally inclined and having their lower edges on the forward side and closely adjacent the bottom of said tank; and at least three inclined tubular scoops mounted on each of said blades and progressively decreasing in diameter toward the ends of said blades, each of said scoops being set at an angle of about thirty degrees to the horizontal and being of sufiicient length to extend above the upper level of the solids in said tank.

3. Agitating apparatus of the character described for a tank adapted to hold a mixture comprising a fluid and solids, including: a vertical rotatable shaft; horizontal blades mounted on said shaft and extending in opposite directions therefrom, said blades being laterally inclined and having their lower edges on the forward side adjacent the bottom of said tank; and a plurality of inclined scoops mounted on said blades, said scoops all having their lower ends forward and progressively decreasing in size toward the ends of said blades.

ANDREAS R. KELLER.

a pair of horizontal blades 

